JPH07138340A - Heat-resistant thermoplastic polyurethane elastomer and its production - Google Patents

Abstract

PURPOSE:To obtain an elastomer highly excellent in heat resistance by selecting a polyurethane which consists of randomly distributed structural units derived from a specific diisocyanate, a specific diol, and a specific compd. and has a specific average mol.wt. CONSTITUTION:This polyurethane elastomer is selected which consists of three kinds of randomly distributed structural units, i.e., (A) structural units of the formula: CONH-X-NHCO (wherein X is one of divalent groups of formula I to IV) derived from a diisocyanate, (B) structural units of the formula: O-Y-O (wherein Y is a divalent group formed by removing terminal hydroxyl groups from an aliph. polyether or polyester diol) derived from an aliph. polyether or polyester diol and having a mol.wt. of 1,000-10,000, and (C) structural units of the formula: O-Z-O (wherein Z is a divalent group of formula V) derived from 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro [5,5]undecane in a molar ratio of A to (B+C) of 1/1 and which has an average mol.wt. of 10,000-200,000.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a novel thermoplastic polyurethane elastomer, and more particularly to a novel polyurethane elastomer having thermoplasticity and excellent heat resistance, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Thermoplastic polyurethane elastomers have long been known in the art. Typical thermoplastic polyurethane elastomers of this type are aromatic diisocyanates, typically 4,4'-diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI) with polyether diols or polyester diols and short chains as chain extenders. It is a linear polymer formed by reaction with glycol. Conventionally, as a polyether diol, the molecular weight is generally about 1,000 to 2,000.
0 poly (oxytetramethylene glycol), poly (propylene glycol) or mixed poly (propylene-
Ethylene glycol) and poly (butylene adipate) or polycaprolactone were used as polyester glycols. As the glycol chain extender, for example, 1,4-butanediol, 1,6-hexanediol, ethylene glycol and diethylene glycol are generally used. In such a thermoplastic polyurethane elastomer, the polyether diol component or polyester diol component has a so-called soft segment,
On the other hand, the portion formed by the reaction between diisocyanate and short-chain glycol constitutes a so-called hard segment. The elasticity as a thermoplastic polyurethane elastomer is due to the microphase-separated structure composed of such soft segments and hard segments.

These polyurethane elastomers are thermoplastic and can be thermoformed by injection such as injection molding and extrusion molding, and are molded into various articles and are commercially available. However, these conventional thermoplastic polyurethane elastomers lose their elasticity at a temperature of about 120 ° C. at most, and therefore their applications are limited to those for which heat resistance is not so required. Therefore, if its heat resistance can be raised to, for example, 150 ° C. or higher, a wider range of applications can be expected. Examples of applications requiring such high heat resistance include heat resistant paints, heat resistant belts, heat resistant hoses, and packing materials.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a polyurethane elastomer which is both thermoplastic and has a high degree of heat resistance.

[0005]

As a result of various studies, the inventor of the present invention has constituted a hard segment by a reaction portion of a specific diol compound containing a spiro ring and an aromatic diisocyanate, while a soft segment has a molecular weight of a certain value or more. It has been discovered that the above objects are achieved when composed of polyether diols or polyester diols having

According to the present invention, the following equation (a)-
A unit derived from a diisocyanate represented by CONH-X-NHCO-, and (b) an aliphatic polyether represented by the formula -O-Y-O- and having a molecular weight in the range of 1,000 to 10,000. A unit derived from a diol or a polyester diol, and (c) 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10 represented by formula —O—Z—O—. -Tetraoxaspiro [5,
5] Units derived from undecane are randomly distributed, and the molar ratio of the unit (a) / the sum of the unit (b) and the unit (c) is 1: 1 and 10,000 to 200,000. A heat resistant thermoplastic polyurethane elastomer having an average molecular weight within the range is provided. However, in each of the above formulas, X is at least one divalent group selected from the group consisting of the following chemical formulas 5, and Y is the aliphatic polyether diol or polyester diol with the terminal hydroxyl group removed. Is a divalent residue, and Z is a divalent group represented by the following chemical formula 6.

[0007]

[Chemical 5]

[0008]

[Chemical 6]

This polyurethane is thermoplastic and can be thermoformed by a thermoforming machine such as a conventional injection molding machine or extrusion molding machine. This polyurethane is an elastomer that exhibits high rubber elasticity from a low temperature of about -50 ° C. The elastomer also has a dynamic storage modulus which does not substantially change from a low temperature such as -50 ° C to a high temperature such as about 190 ° C, and exhibits extremely high heat resistance which is exceptional as an elastomer.

The above-mentioned polyurethane elastomer of the present invention can be manufactured by a so-called one-shot method. That is,
(A ′) diisocyanate compound, (b ′) aliphatic polyether diol or polyester diol and (c ′) 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10 -Tetraoxaspiro [5,5] undecane (trade name: spiroglycol) is mixed and subjected to a polyaddition reaction for a required time to obtain a target polyurethane elastomer.

The diisocyanate compound that can be used in the above reaction is represented by the general formula OCN-X-NCO, where X is as defined for formula (a) above. In the range examined by the present inventor, the intended thermoplastic polyurethane elastomer having high heat resistance could not be obtained by using a diisocyanate other than these. Specific examples of the diisocyanate compound include p-phenylene diisocyanate,
Toluene-2,4-diisocyanate, toluene-2,
There are 6-diisocyanates and 4,4'-diphenylmethane diisocyanates. These diisocyanate compounds may be subjected to the reaction as a mixture of two or more. Of these diisocyanate compounds, the most preferred at present is 4,4'-diphenylmethane diisocyanate (MDI).

In the method of the present invention, the polyether diol or polyester diol reacted with the diisocyanate compound has a molecular weight of about 1,000 to about 10,
If the condition of 000 is satisfied, all of the aliphatic polyether diols and polyester diols commonly used in the synthesis of polyurethane can be used. When the molecular weight is 1,000 or less, it is generally not possible to impart desired heat resistance to the polyurethane elastomer. Examples of suitable polyether diols or polyester diols for use are polyether diols such as poly (oxypropylene glycol), mixed poly (oxypropylene-ethylene glycol), polycaprolactone and poly (oxytetramethylene glycol), and poly (oxypropylene glycol). There are polyester diols such as tetramethylene adipate).
Generally, polyether diols are preferable to polyester diols, and poly (oxytetramethylene glycol) is particularly preferable.

In the method of the present invention, another essential component which is reacted with the diisocyanate compound together with the diol component is 3,9-bis (1,2) which is also a diol.
1-dimethyl-2-hydroxyethyl) -2,4,8,
It is 10-tetraoxaspiro [5,5] undecane. According to the research by the present inventor, this 3,9-bis (1,
1-dimethyl-2-hydroxyethyl) -2,4,8,
When a hard segment is composed of 10-tetraoxaspiro [5,5] undecane and a diisocyanate compound, 1,4 used in the production of conventional thermoplastic polyurethane elastomers, for example, in polyurethane elastomers
-It has been revealed that extremely high heat resistance, which cannot be achieved by a chain extender composed of a short chain glycol such as butanediol, 1,6-hexanediol, ethylene glycol and diethylene glycol, can be imparted. .

In the above method, the diisocyanate component (a '), the diol component (b') and 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,
The 4,8,10-tetraoxaspiro [5,5] undecane component (c ′) is used in the reaction at a molar ratio of 1: 1 (a ′) / (b ′) and (c ′). It However, as is well known, the isocyanate compound may be partially deactivated due to environmental moisture during storage and / or use, so that a slight excess of diisocyanate is usually used in order to guarantee that amount. That is, diisocyanate is used in an excess of about 1 to 5 mol% of its stoichiometric amount.

The above reaction should be carried out in an inert atmosphere. A rare gas such as neon or argon and a nitrogen gas can be generally used as the inert atmosphere, but the nitrogen gas is generally used from the economical point of view. This reaction can be carried out in an inert solvent or without solvent. When the reaction is carried out in an inert solvent, the concentration of all reactants generally ranges from about 10 to about 50.
Weight / volume%, preferably about 20 to about 40 weight / volume%.
Is preferred. As the inert solvent, for example, toluene, anisole, dimethyl sulfoxide, etc. can be preferably used.

The polyaddition reaction of the present invention is usually carried out at room temperature to 130.
C., preferably at a temperature in the range of about 50-100.degree. The reaction time is the desired molecular weight, namely 10,000 to 2
The reaction time is usually about 4 to about 10 hours in the above temperature range, although the time is sufficient to obtain an average molecular weight of 0,000, and a polyurethane elastomer having the desired molecular weight is obtained. This reaction proceeds sufficiently even without a catalyst, but can be carried out in the presence of a catalyst if desired. As the catalyst, those usually used in the synthesis of polyurethane can be used in a usual amount. Representative examples of such catalysts include organic metal catalysts such as dibutyltin dilaurate and amine catalysts such as triethylamine.

In the polyurethane elastomer of the present invention produced as described above, the diol component (b ') constituting the soft segment and the diol component (c') constituting the hard segment are randomly mixed with the diisocyanate component (a '). Is a polymer that is bound and distributed in.

The polyurethane of the present invention generally has about 1
It has an average molecular weight of 10,000 to about 200,000.
As mentioned above, this polyurethane is an elastomer that exhibits thermoplasticity, can be easily molded by a conventional thermoforming method such as injection molding, extrusion molding, or compression molding, and has a high level of elastic modulus. This high elastic modulus (dynamic storage elastic modulus) has a wide temperature range, for example, about -50 to about + 190 ° C.
It is maintained over the temperature range of, and does not change substantially at temperatures above room temperature. The fact that the high elastic modulus is maintained even at a high temperature in this way means that the soft segment and the diisocyanate composed of the polyether diol or polyester diol in the polyurethane elastomer of the present invention and 3,9-bis (1,1-dimethyl- 2-Hydroxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane is a microphase-separated structure composed of hard segments composed of reaction moieties, that is, a sea-island structure at such a high temperature. It means that the polyurethane elastomer of the present invention has such a property even though its diol components (b ′) and (c ′) are randomly distributed in the molecule as described above. It is extremely surprising that it has excellent heat resistance.

[0019]

The invention will now be illustrated by the examples. However, it goes without saying that the present invention is not limited to these examples.

Example 1 A 1 L (liter) four-necked separable flask equipped with a stirrer equipped with a torque meter, a thermometer, a dropping funnel and a nitrogen introducing tube was charged with 30 parts of 4,4'-diphenylmethane diisocyanate (0.2 mol). 30% by weight of poly (oxytetramethylene glycol) (molecular weight about 3000; 0.1 mol) which was previously purified by a reduced pressure azeotropic distillation method under a nitrogen atmosphere while stirring the solution containing a weight / volume% anisole solution. Volume% anisole solution and 3,9-bis (1,1-
Dimethyl-2-hydroxyethyl) -2,4,8,10
A solution of tetraoxaspiro [5,5] undecane (0.1 mol) in 30% w / v dimethylsulfoxide was added. The resulting mixture was heated to 80 ° C. and reacted at this temperature for about 10 hours. The resulting reaction mixture was a colorless, transparent solution. This solution was poured into methanol to precipitate the polymer, which was suction filtered with an aspirator to separate the polymer by furnace. The polymer was redissolved in dimethylformamide, and the above-mentioned purification operation was repeated twice more, followed by drying at room temperature and a reduced pressure of about 40 mmHg for about 1 week, and finally vacuum drying at room temperature to a constant weight.

The polymer obtained was a substantially white powder with a yield of about 80%. The molecular weight of this polymer was about 100,000. The elemental analysis value was in good agreement with the theoretical value, and it was the target thermoplastic polyurethane elastomer.

The relationship between the dynamic storage elastic modulus of this polyurethane elastomer by the free damping torsional vibration method and the temperature is shown as a curve SPG-3000 (2) in FIG. This curve shows that the polyurethane produced as above is 170
It shows that it maintains a very high elastic modulus even at a temperature of up to 190 ° C. and has extremely excellent heat resistance.

Example 2 The procedure of Example 1 was repeated except that poly (oxytetramethylene glycol) having a molecular weight of about 3,000 in Example 1 was replaced with poly (oxytetramethylene glycol) having a molecular weight of about 2,000. I repeated. The resulting polyurethane was also a thermoplastic elastomer. FIG. 1 shows the relationship between the dynamic storage elastic modulus and temperature of this polyurethane elastomer.
Curve SPG-2000. In this curve, the polyurethane produced as described above also showed the same change in elastic modulus as the polyurethane elastomer of Example 1, and the elastic modulus was not substantially decreased up to a temperature of about 180 ° C. .

Example 3 The procedure of Example 1 was repeated except that the poly (oxytetramethylene glycol) having a molecular weight of about 3,000 in Example 1 was replaced with poly (oxytetramethylene glycol) having a molecular weight of about 4,000. I repeated. The resulting polyurethane was also a thermoplastic elastomer. FIG. 1 shows the relationship between the dynamic storage elastic modulus and temperature of this polyurethane elastomer.
As curve SPG-4000. In this curve, the polyurethane produced as described above also showed the same change in elastic modulus as the polyurethane elastomer of Example 1, and the elastic modulus was not substantially decreased up to a temperature of about 190 ° C. .

[0025]

The physical property of the elastomer such as the present material is, of course, its rubber elasticity.
Materials utilizing this property include (1) various hose materials, (2) packing materials, (3) vibration damping materials, (4) building materials,
(5) Fiber materials and the like can be mentioned. The polyurethane of the present invention has the property that the elastic modulus value is substantially constant in a wide temperature range from room temperature to about 190 ° C. and is heat resistant as described above. This is a very important and useful advantage in applications.
Moreover, since the polyurethane of the present invention can be easily processed by injection molding, extrusion molding or the like without performing vulcanization like conventional crosslinked rubber, it is possible to reduce the facility, simplify the facility, and eventually reduce the cost. However, the industrial and economic effects are also extremely large.

[Brief description of drawings]

FIG. 1 is a graph in which the dynamic storage elastic modulus of the ether-based polyurethane of the present invention is plotted with respect to temperature, and a curve SPG-3000 (2) shows poly (oxytetramethylene glycol) having a molecular weight of about 3,000. , Curve SPG-
2000 is the modulus of elasticity of polyurethane synthesized using poly (oxytetramethylene glycol) having a molecular weight of about 2,000, and curve SPG-4000 is poly (oxytetramethylene glycol) having a molecular weight of about 4,000. The relationship of each is shown.

Claims (2)

[Claims] 1. A unit derived from a diisocyanate represented by the following formula (a) —CONH—X—NHCO—, and (b) 1,000 to 10, represented by the formula —O—Y—O—.
A unit derived from an aliphatic polyether diol or polyester diol having a molecular weight in the range of 000, and (c) 3,9-bis (1, represented by the formula —O—Z—O—
1-dimethyl-2-hydroxyethyl) -2,4,8,
Units derived from 10-tetraoxaspiro [5,5] undecane are randomly distributed, and units (a) /
The molar ratio of the sum of units (b) and units (c) is 1: 1;
A heat resistant thermoplastic polyurethane elastomer having an average molecular weight in the range of 10,000 to 200,000. However, in the above formulas, X is at least one divalent group selected from the group consisting of the following chemical formulas 1, and Y is a divalent group obtained by removing the terminal hydroxyl group from the aliphatic polyether diol or polyester diol. And Z is a divalent group represented by the following chemical formula 2. [Chemical 1] [Chemical 2] 2. A diisocyanate represented by the formula (a ′) represented by the general formula OCN-X-NCO, wherein X is at least one divalent group selected from the group consisting of the following chemical formulas: b ') an aliphatic polyether diol or polyester diol having a molecular weight in the range of 1,000 to 10,000 and (c') 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2 , 4,8,10-Tetraoxaspiro [5,5] undecane was mixed at a molar ratio of 1: 1 of component (a ′) / component (b ′) and component (c ′) to obtain The mixture is subjected to a polyaddition reaction in an inert atmosphere in an inert solvent or without a solvent at a temperature in the range of room temperature to 130 ° C. for a time sufficient to obtain a target molecular weight. ) Formula-CONH-X-N
A unit derived from the diisocyanate represented by HCO-, (b) a unit derived from the aliphatic polyether diol or polyester diol represented by the formula -O-Y-O-, and (c) a formula -O. The 3, represented by -ZO-
9-bis (1,1-dimethyl-2-hydroxyethyl)
A unit derived from -2,4,8,10-tetraoxaspiro [5,5] undecane (wherein X is as defined above and Y is a terminal hydroxyl group derived from the aliphatic polyether diol or polyester diol). A divalent residue in which the group has been removed, and Z is a divalent group represented by the following Chemical formula 4) is randomly distributed, and the unit (a)
/ A method for producing a heat-resistant thermoplastic polyurethane elastomer having an average molecular weight in the range of 10,000 to 200,000, wherein the molar ratio of the sum of units (b) and units (c) is 1: 1. [Chemical 3] [Chemical 4]